This application relates generally to a disc drive and more particularly to a self-biasing spindle motor connector.
A spindle motor connector of a disc drive provides commutation power to a spindle motor. The spindle motor connector also senses the correct spin-up direction and provides back electromotive force (BEMF) sensing information to control the speed and direction of the spindle motor. The spindle motor connector controls these functions via a number of alloy contacts (on the connector) that connect to pads (on a printed circuit board). Spindle motor connectors are typically assembled into a disc drive by locating the spindle motor connector into a hole and against a surface of a base plate of the disc drive.
Depending on a given disc drive system""s tolerance build-up, making the contact between the spindle motor contacts and the pads of the printed circuit board (PCB) may be problematic. For example, cast and machined features control the amount that the spindle motor connector moves in an x-y plane. However, movement in the x-y plane may contribute to the problem as may rotational movement which tends to be magnified. Rotational tolerance refers to the amount that the spindle motor connector is allowed to rotate due to its fit with mating features. The combined effect of rotational movement and movement in the x-y plane determines whether the connection between the contacts and the pads is reliably made.
Another problem in disc drives is that the contacts may be at some distance from the origin point that controls the movement of the spindle motor connector in the x-y plane. Thus, when the spindle motor connector rotates about the origin, the contact points that interface with the PCB pads swing through a large angle. At large angles this swinging may prevent the assembly from working as there must always be at least a certain minimum amount of overlap between the contacts and the pads on the PCB for the assembly to function. Moreover, the contacts, if misaligned, may connect with adjacent pads. Although the pads may be made larger to connect with the proper contacts, the pads may not be made excessively large because PCB space is limited.
A typical method to rotationally bias, i.e. control the rotation, of a spindle motor connector is to fix the connector in position with assembly tooling until an adhesive cures. Another method is to add precise locating features through additional machining, pressed-in place pins or other fixtures. However, these methods are time-consuming or require additional costly tooling and fixtures. There are also additional inspection costs due to the need to verify the accuracy of the tooling.
Accordingly, there is a need for a spindle motor connector that may be assembled into the base plate without the need for using a fixture. There is a further need for a spindle motor connector that enhances throughput capability while saving on the cost of fixturing or eliminating the need for such assembly tooling altogether. There is a further need for a spindle motor connector that is self-biasing and maintains its position. Thus, there is a need for a method for assembling a spindle motor connector that is self-biasing and does not require additional tooling and fixtures or additional costly machining.
The present invention provides a solution to this and other problems, and offers other advantages over the prior art.
Against this backdrop the present invention has been developed. In one embodiment, the present invention is a spindle motor connector that provides its own rotational bias without the need for a separate fixture. In one embodiment, the present invention enhances throughput capability and eliminates the fixtures and tooling found in the prior art, thereby saving costs. In one embodiment, the present invention also does not occupy valuable space on the PCB that may be needed for other components.
In one embodiment of the present invention, the invention comprises a self-biasing spindle motor connector for a disc drive. The spindle motor connector includes a body portion and a plurality of alloy contacts extending away from the body portion. The alloy contacts are used for connecting to pads on a disc drive printed circuit board. The connector may comprise a crush rib extending from at least one side of the body portion and making contact with a vertical wall (locating edge) of a base plate of the disc drive. The crush rib ensures that the connector is properly biased and situated in relation to the base plate and the disc drive printed circuit board. The body portion may also include an extending member to provide an alignment feature for the printed circuit board as it is assembled to the disc drive and helps align the PCB pads to the alloy contacts of the connector. The connector may also include an x-y control boss. The x-y control boss limits the connector""s movement in an x-y plane whereas the crush rib restricts the connector""s rotational movement. The x-y control boss mates with a corresponding hole (opening) in the base plate.
In yet another embodiment, the connector may also include a rotational control boss that is inserted into a rotational control hole (opening) of the base plate to limit rotational movement of the connector. The connector may also include support legs that prevent the alloy contacts from being damaged by the load from the PCB.
An embodiment of the present invention may be implemented as a method for assembling a disc drive by inserting a spindle motor connector into a base plate of the disc drive such that a rotational boss of the connector is inside a rotational control opening of the base plate and such that an x-y control boss of the connector is inside an x-y control opening of the base plate. The method may also include the step of inserting a disc drive printed circuit board (PCB) on the base plate such that a plurality of alloy contacts on the connector come into contact with a plurality of pads of the PCB.
These and various other features as well as advantages which characterize the present invention will be apparent from a reading of the following detailed description and a review of the associated drawings.